Abstract
The advanced biodegradation process of atrazine was stimulated with hydrogen peroxide (H(2)O(2)) in a sequencing batch reactor (SBR) under different operational conditions due to in situ generation of H(2)O(2)-peroxidase. The complete biodegradation and mineralization of 50 mg/L atrazine was achieved in the SBR with a biomass concentration of 328 mg/L stimulated with 10 mM of H(2)O(2). The presence of H(2)O(2) in the SBR induced the generation of H(2)O(2)-peroxidase resulted in acceleration of atrazine biodegradation. Adding moving media to the SBR system and converting it to the MSBR considerably improved the rate of atrazine biodegradation and mineralization under H(2)O(2) mediation. The highest specific utilization rate of atrazine in the SBR operated at the biomass concentration of 55 mg/L was 19.4 mg/g(biomass).h, while it was 33.5 mg/g(biomass).h in the MSBR operated at the biomass concentration of 37 mg/L. The low ATZ removal along with no peroxidase activity in the bioreactor in absence of H(2)O(2) clearly ideated that the biodegradation and mineralization of ATZ was considerably mediated by H(2)O(2)-peroxidase enzyme. The toxicity of atrazine solution decreased markedly when treated in the MSBR under optimum conditions. Accordingly, the MSBR stimulated with H(2)O(2) is an efficient and thus promising process for biodegradation of recalcitrant compounds.